Most modern Save Editors for Angry Birds Epic function by modifying the player.json file. Since the game stores much of its progress locally, you can use a file explorer or a dedicated web-based JSON editor to change values.
Setting values too high (e.g., entering a number higher than angry birds epic save editor top
Which (Coins, Mastery, or Weapons) are you trying to unlock? Most modern Save Editors for Angry Birds Epic